Speed reducer and positioning device

ABSTRACT

Two mechanical elements are mounted for independent rotation in the same direction about a common a axis. The difference of the rates of rotation of the two mechanical elements is converted into a resultant mechanical rate of rotation of an output shaft. An electrical element may be mounted on each of the mechanical elements in electrical coactive relationship providing a variable electrical value dependent on the relative angular displacement of the two mechanical elements when the electrical elements are connected into an electrical circuit.

United States Patent Wah berg [451 Aug. 22, 1972 [54] SPEED REDUCERPOSITIONING 3,273,421 9/1966 Jones ..74/705 DEVICE 3,405,571 10/1968Mersch ..74/674 [72] Inventor: Eric C wamberg, 32 8th St Stam 3,429,2002/1969 Green ..74/674 ford Conn 06905 Primary Examiner-Arthur T. McKeon[22] Filed: June 1, 1970 Attorney-Alfred E. Miller [21] Appl. No.:41,820 [57] ABSTRACT Two mechanical elements are mounted for indepenl5U.S. Cl ..338/162, 3 17/249 R, 3177121585, dent rotation in the samedirection about-a common a [51] Int Cl H01 c 5/02 Holh 85/141101}! 85/16axis. The difference of the rates of rotation of the two [58] Field74/705 674 5 338/l45 mechanical elements .is converted into a resultantn 3517/2219 R 249D mechanical rate of rotation of an output shaft. An velectrical element may be mounted on each of the mechanical elements. inelectrical coactive relationship [56] Referevnc'es Cned providing avariable electrical value dependent on the UNITED STATES PATENTSrelative angular displacement of the two mechanical 3 360 757 12/1967wah'lbrg 338/162 elements when-the electrical elements are connected t't 3,560,906 2/1971 Wahlberg ..338/162 x o a elec m 1,445,741 2/1923Blackwell ..74/705 7 Claims, 7 Drawing Figures I 37 i L/ 33 'l '51, I Pi31a SPEED REDUCER AND POSITIONING DEVICE This invention relates tomechanical devices normally known as gear reducers, speed reducers andpositioning devices. The invention is further related to such devices asabove wherein the relative rate of speed or the relative position of theoutput shaft is remotely indicatable by electrical elements included onthe mechanical devices and connected into suitable electrical circuitry.

An object of this invention is to provide a novel unusually large ratiogear reduction device.

Another object of this invention is to provide a unit using spur andinternal gears. Another object is to provide an electrical output whichis responsive to the angular position of the mechanical device.

Other objects of the invention will become evident from the broadinterpretations of the specifications and the drawings. I

These and other objects of the invention are achieved in an arrangementwherein a pair of elements such as discs'of different diameters are freeto rotate about a common shaft. The rotation may be caused by therotation of a rotatable member having two different diameters matingwith the circumferences of the aforementioned elements. The radius ofone element added to the radius of the diameter of the rotatable membercooperating with that element must equal the radius of the secondelement added to the other diameter of the rotatable member mating withthat element. Sun gears are provided to transfer the motion of theelements to corresponding planet gears which are independently androtatably mounted to on pins integral with a disc rotatably mounted onthe shaft supporting the aforesaid elements. One group of planet gearsmeshes with the sun gear of one element and a stationary internal gearmounted in the housing of the unit. The other group of planet gears meshwith the sun gear of the other element and the internal gear of theoutput shaft. As a result, the ratio of the input speed to the rotatablemember to the output speed will be the difference of the cumulativeratios of the gear trains associated with the respective elements.Proper mounting of electrical elements on the mechanical elementstogether with terminals and pick-off provide an electrical outputrepresentative of the position of the elements. The assembly iscompactly contained in a housing to form a compact product according tothe invention.

One embodiment of the invention is illustrated in FIGS. 1-7 in which;

FIG. 1 illustrates a side view of the invention;

FIG. 2 is a cross-section of FIG. 1;

FIG. 3 is a cross-section of the invention taken along lines 3-3 of FIG.2; v

FIG. 4 is a cross-section of the invention taken along line 44 of FIG.2;

FIG. 5 is a cross-section of the invention taken along lines 5-5 of FIG.2;

FIG. 6 is a frontal view of the planetary gearing assembly; and

FIG. 7 is a side view of the planetary gearing assembly.

Other embodiments are afforded by this invention with variablecondensers, impedance, etc. in which similar mounting on the mechanicalelements when rotated they are properly identified with each other as toelectrical'properties and mechanically. Also a plu- I rality of theseassemblies may be operated from one input to obtain several outputswhich are similar or different. It is therefore important not to limitthe scope of this invention to those embodiments illustrated butconsider it in the broadest aspect.

Reference is now made to FIGS. l-7 which illustrate one embodiment ofthe invention. Included in the embodiment is case 42, cover 43, shaft16, upper cover 44, upper disc 32, lower disc 31, pinion shaft 14,terminals 29, 23, 37a, sliding contact 38 attached to conductive ring 26located on the under side of upper disc 32, sliding contact 37 slidingon ring 26, and a resistive layer 30 located on the upper surface of thelower disc 31. Sliding contact 38 slides on the resistive layer 30.Sliding contact 37 extends out of the housing 42 to form terminal 37a.Terminals 29 and 23 extend into housing 42 and contact respectiveconductive rings located on upper surface of lower disc 31 and eachFollowing the electrical path we find that terminal 29 may be used asone connection point from where current will travel to resistive layer30 to terminal 23. Also, it may travel to resistive layer 30 to slidingcontact 38 to contact 37 which becomes terminal 37a outside the case 42.The amount of resistance included in the second path is dependent uponthe position of sliding contact 38 on resistive layer 30. This in turnis dependent upon the positions of the discs 31 and 32. The position ofdiscs 31 and 32 are determined by the rotation of pinion shaft 14. I

Disc 31 is rotatably mounted on shaft 35. Disc 32 is larger in diameterthan disc 31 and is fixedly mounted on shaft 35 by means of key 39 andlocated just above disc 31. Each have, for the purpose of thisdescription, gear teeth on their circumferences.

Pinion shaft 14 has two sets of gear teeth-one set having a differentpitch diameter than the other set. The smaller diameter matches, whenassembled to the unit, with the larger diameter upper disc 32 gear teethand the larger diameter pinion gear matches the smaller disc 31 gearteeth. In each case, the sum of the pitch radii and the disc gear mustequal the center line distance between the shaft 14 and 35. Thus, whenpinion shaft 14 is turned, both discs will also rotate and in proportionto the circumferences of the contacting gears. Large disc 32 will turnslower than small disc 31 in that circumference travel of the smallerpinion gear is less than that for the larger pinion gear which drivesthe smaller disc 31. Thus, though both discs are rotating as a result ofrotation of the pinion shaft, the smaller disc will be going faster and,after a predetermined number of turns of the pinion shaft 14, will lapdisc 32. Thus, with proper design, very high accuracy may be obtainedfrom small increments of rotation of the pinion shaft 14 applied todisplace discs 31 and 32.

The shaft 35 has a gear 21 located near the end opposite to that havingthe keyway. The same type of gear is placed on the under side of gear31. A planet gear holder 15 is located between the lower disc gear 31and gear 21 on shaft 35. The gear holder 15 is rotatably mounted forindependent rotation on shaft 35. In FIG. 6 and 7 there are shown twosets of planet gears having three gears each. Planet gears 17, 17a, and17b are located on one side of the planet gear holder 15 and the secondset of planet gears 20, 20a, and 20b are located on the other side ofthe planet gear holder. Each of the gears is mounted to an axlerespectively 25, 25a, and 25b with the other set of planet gearssimilarly mounted to axles. Each gear is free to rotate about therespective axle.

However, when the planet gear assembly is assembled tothe shaft 35,planet gears 17, 17a, and 17b mesh with gear 41 on disc gear 31 and withan internal gear 40 mounted fixedly to the housing 42. The other set ofplanet gears 20, 20a, and 20b mesh with gear 21 on shaft 35 and withinternal gear 50 attached to output shaft 16. Shaft 35 is mounted incover 44 and output shaft 16.

The shaft 14 may be rotated by the use of a knob or as is shown by. amotor or other means to adjust the output shaft for speed or forpositioning to very accurate angular position.

When disc gear 31 is driven by gear 12 gear 41 drives planet gears '17,-17a, and 17b which in turn drive against stationary internal gear 40 todrive planet gear holder 15. When disc gear 32 is driven by gear 11shaft 35 is rotated through key 39. This causes integral gear 21 torotate and planet gears 20, 20a, and 20b to rotate.

Since planet gear holder 15 is already rotating, planet gears 20, a, and20b would be rotating around gear 21. But gear 21 is rotating in thesame direction as gear 41 and at a slower speed. Therefore, gears 20,20a, and 20b will be rotating around their respective axles 25, a, and25b at a slower speed than gears 17, 17a, and 17b. Since internal gears50 and 40 are identical and gear 40 is stationary, gear 50 will rotateat a rate of speed which is the difference between the speeds of discgears 32 and 31. The direction of rotationwould be the same as that ofthe planet gear holder 15.

Should the speed of rotation of gear 21 be greater than that of gear 41,the direction of rotation would be opposite to that of planet gearholder 15. The direction of rotation of the output shaft 16 will depend,therefore, on whether gear 21 is slower or faster than gear 41 and,consequently, the disc gear 31 and 32 size relationship. The planet gearholder 15 will rotate in the same direction as the gear 41 and,therefore, gear disc 31.

The speed reducer can be further refined by alteration of the planetgears 17 and 20 and gears 41 and 21 respectively either collectively orindividual sets.

Smaller units may be molded plastic parts while larger units may be madeof castings or machined parts. Bearings are added as needed for castingassemblies and machined parts.

By mounting the stationary plates of a condenser on disc 31 and themoveable plates on the disc 32 and cally and electrically determine thisdifference and represent this difierence electrically and mechanically.The difference is mechanically represented by the motion or position ofthe output shaft. The method is simple, requiring few parts, may beminiaturized, and may be manually, motorized and remotely controlled.Units may be designed for a plurality of similar or different or acombination of similar and different outputs from one input. Other unitsmay be designed for more than one input by driving each of the piniongears 11 and 12 from a separate source in which one of the gears wouldbe free to rotate on shaft 14. It is therefore important that, while Ihave described embodiments of my invention in this application, it isnot the intent to limit the scope of these since the invention may beused to control'rnany types of mechanical and electrical devices withproper coordinated design. Therefore the claims appended hereto shouldnot belimited to the embodiment shown. Iclaim: v

1. A device for connection to a mechanism for adjusting to aselected-mechanical value from a mul tiplicity of mechanical values insaid mechanism, compair of elements and responsive thereto fordetermining holding their space relationship by locating discs 32 Y and31 accurately from each other is it easily seen that this invention isapplicable to this variation as well as other electrical and mechanicalassemblies where accurate positioning or high speed reductions isimportant.

There has accordingly been described and shown herein a novel and newmeans for obtaining unusually high ratio gear reduction in a small unittogether with a novel means to indicate the rate of speed and/or theaccurate positioning of the output shaft. There has also been describeda novel means for rotating two or more items at relative speeds to eachother and to mechanithe difi'erence of said rate of displacement of eachof said pair of elements; and an output means co-acting with andresponsive to said second means.

2. The device as defined in claim 1 wherein one of said pair of elementsincludes a first disc having an electrical surface layer deposited onits face and the other of said pair of elements includes a secondelectrical surface layer mounted on its face, and said electricalsurface layers of said first and second discs being in electricallyco-acting relationship with each other, said electrical surface layer ofsaid first disc including a resistive layer and said electrical surfacelayer of said second disc including electrical contacts slideablecontacting with said resistive layer of said first disc.

3. A device for connection to a mechanism for adjusting to a selectedmechanical value from a multiplicity of mechanical values in saidmechanism com-' prising a housing, a pair of elements mounted in saidhousing for independently rotating about a common axis; a first meansfor rotating one element of said pair of elements, said first meansincluding a rotatable member engageable with said one element of saidpair of elements; a second means for rotating the second element of saidpair of elements, said second means including a rotatable memberengageable with said second element of said pair of elements; a thirdmeans mounted in said housing independently rotating about said commonaxis and coacting with each of said ele-' ments for determining thedifierence of rate of displacement of each elements of said pair ofelements including a double planetary gear reduction assembly; and anoutput means co-acu'ng with and responsive to said third means toprovide an output which represents the rate of displacement of said pairof elements.

4. The device as defined in claim 3 wherein said double planetary gearreduction assembly includes a planet gear holder, a first set of planetgears and a second set of planet gears both mounted on said planet gearholder, a stationary internal gear mounted on said housing and arotatable internal gear mounted integrally to said output means, saidfirst set of planet gears coacting with said one element of said pair ofelements and said stationary internal gear, said second set of planetgears coacting with said second element of said pair of elements andsaid internal gear mounted integrally to said output means;

5. The device as defined in claim 3 wherein said pair of elementsinclude toothed elements and said rotatable member includes toothedmembers engageable with said toothed elements. a

6. The device as defined in claim 3 wherein said pair of elementsincludes a first element having an electrical surface layer deposited onits face and a second element having an electrical surface layer mountedon its face, said surface layers of said first and second ele- 6 mentsbeing inelectrically coacting relationship with each other, saidelectrical surface layer of said first element including a firstcondenser element and said electrical surface layer of said secondelement including a second condenser element co-actively spaced withsaid first condenser element.

7. A device for connection to a mechanism for adjusting to a selectedmechanical value from a multiplicity of mechanical values in saidmechanism comprising a housing, a first and second group of elementseach having at least one gear being mounted in said housing forindependent rotation about a common axis; a first means forsimultaneously rotating each of said gears in the same direction, saidfirst means including a rotatable drive means engageable with each ofsaid gears in response to rotation of said drive means, the rate ofdisplacementof said gears being difierent with respect to eachother; asecond means coacting with one of said gears in one of said groups ofelements and responsive thereto for determining the difierence of I saidrate of displacement of each of said gears; and an second means.

1. A device for connection to a mechanism for adjusting to a selectedmechanical value from a multiplicity of mechanical values in saidmechanism, comprising a housing, a pair of elements, means mounting saidelements in said housing for independent rotation about a common axis; afirst means for simultaneously rotating each of said pair of elements inthe same direction, said first means including a rotatable drive memberengageable with each of said pair of elements for angular displacementof said elements in response to rotation of said drive member, the rateof displacement of said elements being different with respect to eachother; a second means being a double planetary gear reduction assemblyco-acting with each of said pair of elements and responsive thereto fordetermining the difference of said rate of displacement of each of saidpair of elements; and an output means co-acting with and responsive tosaid second means.
 2. The device as defined in claim 1 wherein one ofsaid pair of elements includes a first disc having an electrical surfacelayer deposited on its face and the other of said pair of elementsincludes a second electrical surface layer mounted on its face, and saidelectrical surface layers of said first and second discs being inelectrically co-acting relationship with each other, said electricalsurface layer of said first disc including a resistive layer and saidelectrical surface layer of said second disc including electricalcontacts slideable contacting with said resistive layer of said firstdisc.
 3. A device for connection to a mechanism for adjusting to aselected mechanical value from a multiplicity of mechanical values insaid mechanism comprising a housing, a pair of elements mounted in saidhousing for independently rotating about a common axis; a first meansfor rotating one element of said pair of elements, said first meansincluding a rotatable member engageable with said one element of saidpair of elements; a second means for rotating the second element of saidpair of elements, said second means including a rotatable memberengageable with said second element of said pair of elements; a thirdmeans mounted in said housing independently rotating about said commonaxis and co-acting with each of said elements for determining thedifference of rate of displacement of each elements of said pair ofelements including a double planetary gear reduction assembly; and anoutput means co-acting with and responsive to said third means toprovide an output which represents the rate of displacement of said pairof elements.
 4. The device as defined in claim 3 wherein said doubleplanetary gear reduction assembly includes a planet gear holder, a firstset of planet gears and a second set of planet gears both mounted onsaid planet gear holder, a stationary internal gear mounted on saidhousing and a rotatable internal gear mounted integrally to said outputmeans, said first set of planet gears co-acting with said one element ofsaid pair of elements and said stationary internal gear, said second setof planet gears coacting with said second element of said pair ofelements and said internal gear mounted integrally to said output means.5. The device as defined in claim 3 wherein said pair of elementsinclude toothed elements and said rotatable member includes toothedmembers engageable with said toothed elements.
 6. The device as definedin claim 3 wherein said pair of elements includes a first element havingan electrical surface layer deposited on its face and a second elementhaving an electrical surface layer mounted on its face, said surfacelayers of said first and second elements being in electrically co-actingrelationship wIth each other, said electrical surface layer of saidfirst element including a first condenser element and said electricalsurface layer of said second element including a second condenserelement co-actively spaced with said first condenser element.
 7. Adevice for connection to a mechanism for adjusting to a selectedmechanical value from a multiplicity of mechanical values in saidmechanism comprising a housing, a first and second group of elementseach having at least one gear being mounted in said housing forindependent rotation about a common axis; a first means forsimultaneously rotating each of said gears in the same direction, saidfirst means including a rotatable drive means engageable with each ofsaid gears in response to rotation of said drive means, the rate ofdisplacement of said gears being different with respect to each other; asecond means co-acting with one of said gears in one of said groups ofelements and responsive thereto for determining the difference of saidrate of displacement of each of said gears; and an output meansco-acting with and responsive to said second means.